POS1297 SACROILIITIS AT DIAGNOSIS ASSOCIATED WITH LESS DISEASE FLARE AFTER STOPPING MEDICATION - OUTCOMES AND PREDICTORS OF A SOUTHEAST ASIAN ENTHESITIS RELATED ARTHRITIS (ERA) LONGITUDINAL COHORT
Authors: K. L. Teh, L. Das, Y. X. Book, T. Arkachaisri
Journal: Annals of the Rheumatic Diseases (2022)

Background ERA is a subtype of Juvenile Idiopathic Arthritis (JIA) characterized by involvement of entheses and axial skeleton. Outcomes have been shown to be poorer compared with oligoarticular and polyarticular JIA 1 . Objectives To assess short-and long-term outcomes and predictors of ERA in a large monocentric cohort in Singapore. Methods Children diagnosed with ERA according to ILAR criteria from 2002 to 2021 at KK Women’s and Children’s Hospital, Singapore, were recruited. Outcome statuses were defined according to the criteria for clinical inactive disease (CID) and complete remission (CR) proposed by Wallace et al. 2 , with additional criteria of no enthesitis and no active sacroiliitis on MRI. Nonparametric descriptive statistics were used. Univariate and multivariate analysis were performed using logistic regression analyses. The significant level was set at &lt; 0.05. Results A cohort of 151 ERA patients (male 86%; Chinese 81%) were included. Median age at onset was 11.9 years (IQR 9.4-13.9) and disease duration was 5.3 years (IQR 2.9-8.4). HLA-B27 was positive in 83% of the patients. At diagnosis, 39% of the patients had sacroiliitis, 46% had hip arthritis, 36% had knee arthritis and 25% had enthesitis. Methotrexate was used in 77% of the patients, while biologics was started in 72% of the patients. CID was achieved in 92% of the patients, of which 27% achieved CID in 6 months or less. Sacroiliitis at diagnosis is an unfavourable predictor of CID at 6 months but not a significant predictor of ever achieving CID. Older age at diagnosis is also an unfavourable predictor of CID ever. Medication was totally discontinued in one third of the patients. Half of them went on to have complete remission (CR) off medication. Favourable predictor includes male gender, while positive HLA-B27 and ANA were unfavourable predictors. Two thirds of the patients with CID had at least one disease flare (23% flared after off medication, 13% flared after CR). Both intra-articular joint injection and anti-TNF use were associated with flare after CID, while anti-TNF use was associated with flare after off medication. Sacroiliitis at diagnosis is a protective predictor of flare after stopping medication. Conclusion Despite a high proportion of ERA patients achieving CID, only one third could stop medication completely with high rates of disease flare even after attaining CR. Unfavourable predictors include older age at onset as well as HLA-B27 and ANA positivity. While sacroiliitis at diagnosis is a negative predictor of CID at 6 months, it is protective predictor of flare after discontinuing medication. References [1]Teh, Kai Liang, et al. “Outcomes and predictors of juvenile idiopathic arthritis in Southeast Asia: A Singapore longitudinal study over a decade.” Clinical Rheumatology 40.6 (2021): 2339-2349. [2]Wallace, Carol A., et al. “American College of Rheumatology provisional criteria for defining clinical inactive disease in select categories of juvenile idiopathic arthritis.” Arthritis care &amp; research 63.7 (2011): 929-936. Table 1. Predictors of outcomes Clinical parameters Univariate analysis Multivariate analysis OR 95% CI p OR 95% CI p CID at 6 months Sacroiliitis at diagnosis 0.187 0.048-0.724 0.015 0.023 0.003-0.177 &lt;0.001 CID ever Age at onset 0.790 0.626-0.998 0.048 0.777 0.605-0.997 0.047 Off medication ever Male 5.029 1.121-22.566 0.035 7.703 1.622-36.575 0.010 HLA-B27 0.374 0.158-0.886 0.025 0.290 0.110-0.764 0.012 ANA 0.104 0.013-0.803 0.030 0.077 0.010-0.613 0.015 Flare after CID Intra-articular injection 2.585 1.116-5.988 0.027 3.205 1.299-7.909 0.011 Anti-TNF 3.683 1.697-7.993 0.001 4.328 1.905-9.832 &lt;0.001 Flare after discontinue medication Sacroiliitis at diagnosis 0.222 0.060-0.821 0.024 0.079 0.009-0.722 0.025 Anti-TNF 17.333 3.696-81.300 &lt;0.001 37.942 4.151-346.841 0.001 CID – Clinical Inactive Disease, TNF – Tumor Necrosis Factor, HLA-B27 – Human Leukocyte Antigen-B27, ANA – Antinuclear Antibodies Figure 1. Probability of attaining outcomes over time Disclosure of Interests None declared